We’ve reviewed the much slower Firewire/USB Western Digital Studio 6TB drives and came away impressed. Those retail for around $430 currently ($270 less than the Thunderbolt version) but use energy efficient (read: slower) internal drives and slower Firewire 800 connectivity options.

Notably B&H Photo and Video is selling the Western Digital MyBook Thunderbolt Duo already with $50 discounts (6TB – $649, 4TB- $549) and tax only in New York but without solid shipping dates.